The present disclosure relates to a receiving apparatus, a packet-boundary determination method, and a computer program.
In circumstances in which fixed-length data packets are transmitted as a byte stream, the position of byte data (a synchronous byte) of a specific value can identify a packet boundary position. For example, JP 2000-507785T discloses a technique of accurately finding out a packet boundary by accumulating byte data of a length corresponding to the certain number of packets (defined as “N”) and by determining a position at which a synchronous byte appears the N times in N cycles each of which is just equal to a packet length, as a packet boundary position.
If the value used as that of the synchronous byte does not appear at the other position in each packet, the above-described technique enables locating a correct boundary position. However, the same value as that of the synchronous byte often appears at the same position in each of a plurality of packets other than the packet boundary position by coincidence, in which case, it may be difficult to discriminate a true boundary position from a false boundary position. This phenomenon is generally referred to as “emulation.”
To address this emulation, as disclosed, for example, in JP H7-79219A, there is known a technique for facilitating distinguishing the true boundary position from the false boundary position or the emulated position resulting from this emulation by determining to arrange a byte or a byte sequence of a certain value at another position besides an existing synchronous byte and confirming whether the byte or the byte sequence of the certain value matches a preset byte or byte sequence.